biology 2

• Nuclein


  Material isolated by Friedrich Miescher when studying pus cells from surgical bandages
• Nucleotides


  Basic units of DNA, composed of a phosphate group, a sugar (deoxyribose), and a nitrogenous base (A, C, G, or T) that encodes genetic information

  
• Nucleic Acids


  Main information-carrying molecules of the cell, determining the inherited characteristics of every living thing by directing the process of protein synthesis
• Nucleic Acids

  • Deoxyribonucleic Acid (DNA)
  • Ribonucleic Acid (RNA)
• DNA Structure

  • Nitrogenous base
  • Pentose sugar (Deoxyribose)
  • Phosphate group
  • Glycosidic bond (connects sugar and base)
  • Phosphoester bond (connects phosphate and sugar)

  
• Nucleoside

  Complex of a sugar and a base, four types present in DNA

  
• Polypeptide chain


  Chain of nucleotides showing sequences of nitrogenous bases
• Purines


  Nitrogenous bases with 2 rings, e.g. Guanine, Adenine
• Pyrimidines


  Nitrogenous bases with 1 ring, e.g. Cytosine, Thymine, Uracil
• DNA Helix

  Twisted ladder-like structure of the two strands of DNA
• The two strands of DNA are antiparallel, meaning they are going in opposite directions
• Rosalind Franklin and Maurice Wilkins performed x-ray crystallography to analyze the structure of DNA
• RNA


  • Single-stranded
  • Has the base uracil instead of thymine
  • Has ribose instead of deoxyribose
  • Product of transcription of DNA
• Amino Acids


  Subunits or monomers of proteins
• Levels of Protein Structure

  • Primary (Amino Acid to Amino Acid, Polypeptides=Peptide Bond)
  • Secondary (Helix or Pleated Sheet, Hydrogen Bond)
  • Tertiary (3D Structure, Covalent and Non-covalent Interactions)
  • Quaternary (Multiple Folded Protein Subunits, Complex Molecular Interactions)
• Protein Data Bank (PDB) is an enormous collection of published experiments on the structure of DNA, RNA and proteins
• Differences between DNA and RNA

  • DNA is double-stranded, RNA is single-stranded
  • DNA has thymine, RNA has uracil
  • DNA has deoxyribose, RNA has ribose

  
• Central Dogma of Molecular Biology


  Describes the flow of genetic information from DNA to RNA to Proteins

  
• DNA Replication


  1. Initiation (Helicase unwinds DNA, Replication Forks, Replication Bubbles)

  2. Elongation (RNA Primase, DNA Polymerase, Leading Strand, Lagging Strand, Okazaki Fragments)

  3. Termination (DNA Polymerase, DNA Ligase)
• Types of RNA

  • mRNA (Messenger RNA)
  • tRNA (Transfer RNA)
  • rRNA (Ribosomal RNA)
  • snRNA (Small Nuclear RNA)
• Transcription (RNA Synthesis)

  1. Initiation (RNA Polymerase, Promoter, TATA Box, Transcription Factors)

  2. Elongation (RNA Polymerase, 5' to 3' Direction, Complimentary to DNA Template)

  3. Termination (RNA Polymerase, Terminator Region)
• Translation (Protein Synthesis)

  1. Initiation (5' G-cap of mRNA, Start Codon AUG, Methionine, P Site, A Site)

  2. Elongation (Codon Recognition, Peptide Bond Formation, Translocation)

  3. Termination (Stop Codon UAA, UAG, UGA)
• When translating an mRNA sequence, first identify the location of the start codon AUG, then divide the succeeding sequence into segments of three nucleotides until a stop codon is encountered